How hard is it to repair a cut dash?

[jonathan-m]

PO's handy work (never mind my jury rigged gauges )




And thanks to fellow member Alan'sClassic I got a replacement center section cut out:





I obviously won't be installing this myself, but I was wondering how big of a job I should expect this to be to have welded in properly. Also, how much of that replacement would you think needs to be used?
I rewired an original radio to interface with an ipod, and I'm itching to try it out, but its kinda hard to do with the grand canyon cut out right where my radio should go.