The משנה ברורה writes that one should eat their Purim Seuda preferrably before noon otherwise it takes away from the כבוד of shabbos. This would seem to mean that you need to finish by noon, if you just start before noon and finish later in the day you will not be hungry for the shabbos meal and this takes away from the כבוד of shabbos.
Nowadays, this is practically impossible given our schedules (megila reading for men then women, giving out משלוח מנות, אבות ובנים, etc.). therefore, many have the minhag to daven mincha at mincha gedola and then have their seuda, however, this is problematic with regards to כבוד Shabbos as well as with regards to the length of the seuda (if you start at 1 and candelighting is 5:15 you can't have a 4 hour seuda).
An interesting alternative suggested by the Rav of my shul is the following. Start your seuda later in the day (a little before Mincha Ketana when it is permissible to start a seuda on erev shabbos) and continue into Shabbos. When candle lighting comes (about 2 hours later), have your wife light candles and you say kaballas shabbos, then make kiddush (without בורא פרי הגפן because you are in the middle of a seuda and you already have made a bracha on the wine) and bring out לחם משנה and give it out. This is the דין found in the gemara pesachim of פורס מפה ומקדש. Then continue the seuda until however late you want. Daven maariv after the seuda (hopefully wth a minyan).
The advantages to this approach are:
1. There is no problem with כבוד שבת because by continuing into shabbos it turns out retroactively that the whole seuda was a seudas shabbos.
2. You are not pressed for time
3. You can tell your kids that this is the weird דין found in פסחים of פורס מפה ומקדש , you get to actually do this.
4. Your wife only has to prepare 1 seuda not 2
In truth point 1 is not so simple, to say that retroactively the whole seuda turns into a seudas shabbos is a חידוש.
In any case it is an interesting situation and should provide food for thought for people.
As always, ask your local Rav before actually doing this.