Welding the hole closed is an easy welding job. Welding the case saver post with the bolt hole back in place is a lot more involved.
I have welded those holes closed on a lot of the LTs without splitting the cases.
Degrease the area and then use a carbide burr to clean the area for about a 1/2" around the hole.
Do not spray the area with brake cleaner or contact cleaner after grinding!!!!!!!!!!!!!!
Find someone in your area that is a good TIG welder. Do not use the alumaweld, it will only make it more difficult to TIG weld when you finally decide to fix it correctly. I looks like about a $30.00 welding job.