I think your wording is confusing, a 1/4 of a quart oil leaking out of the seal over a weekend......... because the oil level should be way below the pan rail seal area

The loss of oil is while the boat is running over the weekend time. Not while sitting for the weekend.

Its actually in the instructions that come with the Mildon pans about keeping it loose.
100% on rtv under the washer, oil will migrate out through the keyway.
Typically we are doing this not in the boat, but when weve had to a strap wrench around the balancer works amongst other things.

I think (hope) my problem was the old balancers had corrosion on them where the seals ride. I "assume" my engine guy followed the instructions during assembly as far as leaving the cover loose while installing the balancer. I will pick up a strap wrench and give that a try. Thanks for your help.

If you are getting garbage service from this guy, given him ample time to respond and he doesn't have enough respect for you to call you back why would you not warn others? Just curious.

Long shot but is the guy on vacation
If he is close to you drop by.
I don't think any engine builder would pay for someone else to do the repair however they might reimburse you for the seals. The problem with "warranty" stuff for boat engines is, and I'm assuming here, that you didn't bring your boat to him so he could pull the engines, rebuild them, and reinstall them? So if you did want a "warranty repair" its reasonable for him to ask you to remove the engines again and drop them off.

Those are all good points. There are a few problems. Last year when he had the engines for the re-builds. I dropped them off Thanksgiving weekend and he said he would have them back in middle to late February. Many things came up on his end and I finally was able to pick them up the first week of May. So there was no way I was taking them back to him. The second problem is, he is more than 700 miles from me, and 2 trips would have cost more than the repairs did. It's funny how he took many calls from me and tried to help. But as soon as I sent him pictures of the seals I haven't heard from him since.

I guess he could be on vacation, but I've texted him with the reason I was texting. A simple I'm on vacation and will get call when I get back would be nice.

Eventually I will probably warn others, but right now I'm giving him the benefit of the doubt. Hoping maybe he will step up, at least call me back and tell me he's not going to take care of it.

The little details matter. You can also get a little chromed 'seal saver', that fits over the balancer seal contact area. More designed for issues where the seal has cut a groove in the contact surface of the metal. So you don't need to replace the whole balancer.

We used the seal savers for the repair along with new seals.

I had a BBC drag engine leak at the rear main due to the reason you mentioned (mild corrosion or pitting on the crank). I had a machine shop polish the crank smooth in this area and it solved the leak at the rear main. Perhaps you can put the balancer in a lathe and polish the area that the seal rides on to eliminate the corrosion.