Considering the only real issues with the Tamiya kit OOB are with body panel fits, you are really taking on an ambitious project! It's a shame that Hobby Design resin isn't better...a lot better, considering the cost.
I've had excellent results w/reshaping resin in hot water, sub-boiling. It becomes very pliable and easy to reshape, but it doesn't turn into a blob. The hardest thing is that it if you need to "re-dip" the part, it will warp all over again so you have to do the repair in sections, or over again.
If you'll be at the ACME February meeting, I can bring my SLR builtups and you can see for yourself where the fit issues are, up close and personal. Final door fit without the frame will probably be good, that is one issue they have...once the glass and door panel is installed, the upper frame sticks out just a bit from the body. Before glass...it fits fine. Since yours is a convertible, you can probably get by with only some minor shaving/sanding of the inner door panel where it meets the door surround on the interior tub.
Hood fit is compromised by the intake part, the attachment boss is too long and needs trimming to get the nose emblem as low as possible.
Even knowing about the fit issues, my second SLR (the 722) gave me more problems than the first...
